The invention relates to a steam-filled treatment chamber.
For quite some time, one has known of the problem posed by falling drops, that condense out of the steam atmosphere on the ceiling of a steam-filled treatment chamber. This problem occurs when solid-shade dyed textile webs are treated in a steam-filled treatment chamber. When a water droplet falls onto a web which has not yet undergone full fixation, the result is an excess of water at this spot, i.e., a variation in concentration. This causes the dye in the web to migrate into the more strongly diluted area. This migration is manifested in a variation in the depth of the color shade, i.e., in a spot which is clearly visible on the finished fabric and which makes this fabric unusable, or in any case causes it to deteriorate in quality. It is, therefore, customary to provide means to prevent the drops from falling.
The EP-A1 175 018 discloses a steam-filled treatment chamber of this type, in which the inner wall of the ceiling is made of metal, such as stainless steel or light metal. The means for preventing drops from falling from the ceiling consist of a heating system which employs heating tubes that are arranged outside of the inner wall. These heating tubes are charged, for example, with steam, hot air, or oil. The heating tubes are distributed in a gap situated between the inner walls and an outer insulation layer. The inner wall, which is made of sheet metal and which borders the treatment chamber is smooth. The heating system keeps the inner wall at the correct temperature, so that no liquid can condense from the steam and no drops will form. However, this entails a design of considerable complexity, because heating tubes are placed over the entire surface of the inner wall.
It is also known to prevent drops from forming without covering the ceiling area of the steam-filled treatment chamber with heating tubes, by providing saw tooth-shaped formations in a cross-section on the ceiling. The condensing liquid flows along the edges of the saw teeth down to their bottom peaks. In this case, additional measures must be provided to prevent dripping, whether in the form of collecting grooves or in the form of heating tubes that run along the peak as disclosed by the German Patent 20 33 527. Here, as well, the complexity of design required to prevent drops from forming is considerable; because of the saw-tooth-shaped formation of the ceiling of the treatment chamber, as well as the additional means required the bottom peaks of the saw teeth.
The object of the present invention is to develop a treatment chamber that prevents the formation of condensation drops which adversely affect the quality of the material being treated, without requiring an additional heating system and by using relatively simple means as described by the present invention.